Thread protectors



Jan. 10, 1956 s. L. PHILLIPS THREAD PROTECTORS Original Filed May 6,1950 fiG.3

INVENTOR. Same-y Z PHILLIPS Ari-0e 5' United States Patent THREADPROTECTORS Stanley L. Phillips, Parkview Village, Ohio, assignor toWedge Protectors, Inc., Cleveland, Ohio, a corporation of Ohio Originalapplication May 6, 1950, Serial No. 160,435, new

Patent No. 2,627,877, dated February 10, 1955. Divided and thisapplication November 1, 1952, Serial No. 318,262

1 Claim. (Cl. 138-96) This invention relates to thread protectors of thekind made from sheet metal and adapted to be applied to the ends ofpipes, conduits, fittings and machine parts to protect the screw threadsof such members against damage from blows or contamination by foreignmatter during handling, shipping and storage.

This application is a division of original application Serial No.160,495, filed May 6, 1950, now Patent No. 2,627,877, granted February10, 1955.

Thread protectors of this kind are usually discarded as scrap materialafter a single use and this makes it necessary that the protectors bemanufactured as economically as possible. There are, however, certainrequisites which must be met in such thread protectors and which haveheretofore prevented the manufacturing cost from being reduced below acertain minimum.

One of these requisites is a certain rigidity and strength needed toprotect the thread against blows and which has heretofore been obtainedby selecting the weight or gauge of sheet metal stock which will providethe required rigidity and strength in the protectors made from suchsheet metal stock. Another such requisite is that the protector have arelatively smooth and finished shape which is devoid of burrs and sharpedges, such that the protectors and the pipes or machine parts to whichthey are applied, can be handled safely and without danger of causingpersonal injury or torn clothing. To provide the protectors with such asmooth and finished shape has heretofore required additional forming andtrimming operations which have materially increased the cost ofmanufacture.

The present invention deals successfully with these problems andprovides a novel construction for a sheet metal thread protector whichwill permit the protector to be manufactured more economically and yetwithout sacrifice in its strength and rigidity or in the smoothness andregularity of its shape.

Another object of this invention is to provide a novel construction fora thread protector of the sheet metal type, in which a hollow annularrim integrally formed on the outer end of the sheet metal sleeve of theprotector provides an annular seat for engagement with the end of thethreaded member and also reinforces and stiifens the protector soefiectively that it can be manufactured from a lighter gauge of sheetmetal without any material sacrifice in rigidity or strength.

A further object is to provide an improved thread protector of thecharacter mentioned in which the hollow annular rim is of a radial widthsuch that the periphery thereof extends beyond the periphery of thethreaded member and which rim periphery has knurling extendingtherearound to facilitate obtaining a secure grip on the protector forapplying the same to the threaded member but more particularly forremoving the protector from such threaded member.

Still another object is to provide an improved thread protector of thischaracter in which a packing is connected with the protector by having aholding portion re 2,538,135 Patented Jan. 10, 1956 tained in the hollowannular rim and such packing is adapted for sealing engagement with theend of the threaded member to which the protector is applied.

Yet another object is to provide an improved thread protector of thekind above referred to and intended for application to an internallythreaded hollow member having an internal chamfer, in which the sheetmetal of the sleeve portion of the protector defines an axially inwardlyconverging annular taper adjacent the hollow annular rim for seatingengagement with the internal chamfer of the threaded member.

Other objects and advantages will be apparent in the following detaileddescription and in the accompanying sheet of drawings in which:

Fig. 1 is an elevation, with portions in longitudinal section, showingone form of the improved thread protector of the present inventionapplied to an internally threaded pipe fitting;

Fig. 2 is an outer end view of the thread protector of Fig. 1 showingthe same in detached relation; and

Fig. 3 is an elevation, with portions in longitudinal section, showing athread protector similar to that of Fig. 1, but which includes a packingelement.

In the embodiment of the invention illustrated in Figs. 1 and 2 a hollowmember or pipe fitting 31 is shown, such as a coupling having aninternal thread 32 therein with a thread protector 33, of the insidetype and embodying the present invention, applied to such coupling inprotective relation to the thread thereof. The coupling 31 is alsoprovided with an inwardly converging annular axial chamfer 34 adjacentits outer end and with which the thread protector 33 cooperates, as willbe presently explained.

The thread protector 33 is a substantially cup-shaped hollow sheet metalmember having a sleeve portion 35 carrying an external helical thread 36adapted for screwed engagement with the thread 32 of the coupling 31.The protector 33 includes a transverse end wall 37 at the inner endthereof and, at its outer end, is provided with a hollow annular bead orrim 38. Between the hollow rim 38 and the thread 36, the protector 33 isprovided with an inwardly converging annular axial chamfer 39.

In accordance with one important feature of the pres ent invention, thehollow annular bead or rim 38 is integrally connected with, and formedby the sheet metal of, the outer end of the sleeve portion 35 and issubstantially radially outwardly offset from the sleeve portion so as tooccupy a position in an outwardly overhanging relation such that it willengage the annular end face 40 of the fitting 31 when the protector isscrewed onto the thread 36. The hollow annular rim 38 is formed by thesheet metal of the outer end of the sleeve portion 35 being deflected soas to extend in an outwardly offset and reversely curled relation asshown in Fig. 1 of the drawing. Such deflection of the sheet metal ofthe outer end of the sleeve portion 35 into this reversely curledrelation to define the hollow annular rim 38 can be accomplished by anysuitable drawing, forming or spinning dies by which sheet metaloperations of this kind are accomplished.

The hollow annnular rim 38 is defined by integral Wall portions of thesheet metal sleeve 35 of the protector and which include a substantiallyradially outwardly extending annular wall portion 38, an axiallyextending annular wall portion 38 and a substantially radially inwardlyextending annular wall portion 38. These annular wall portions 38 38 and38 are integrally connected continuous portions of the sheet metallocated at the outer end of the sleeve 35 and constitute theabove-mentioned outwardly deflected and reversely curled sleeve portionswhich define the hollow annular rim 38. As shown in Fig. 1, the inwardlyextending annular portion 38 approaches, but preferably does u notengage, the wall defining the main portion of the sleeve 35.

When the thread protector 33 is applied to the fitting 31, the outwardlyoffset hollow annular rim 38 engages the end face 40 of the fitting and,in cooperation with the thread 36, produces a wedged or lockedengagement on the fitting for retaining the protector thereon. Thehollow annular rim 38, and particularly the inwardly deflected annularportion 38 thereof, will be capable of some springing or yielding whenthe protector is applied to the fitting for producing this lockedC'l'iCCt and also as the result of blows delivered against the outer endportion of the protector during handling or shipping of the fitting.Since the annular rim 33 is hollow and has this limited yielding orspringing characterist'ic, it will readily absorb such blows or jars andprevent the same from damaging the threaded end of the fitting.

As another feature of this invention, the improved thread protector 33is constructed so that the hollow annular rim 38 will have a radialwidth such as to locate the outer periphery of the rim at a pointoutwardly of the outer surface or periphery of the fitting 31 and thisouter periphery of the rim is provided with knurling 41. When the hollowannular rim 38 has such an increased radial widthand carries theknurling 41 on its outer periphery, an appropriate tool or a securehandgrip can be applied to the protector for more easily unscrewing thesame from the threaded fitting 31' when the protector is to be removed.

. One important advantage resulting from the above describedconstruction for the thread protector 33 is that the hollow annular rim38 reinforces and stiffens the sheet metal sleeve 35 to such an extentthat the protector can be made from a much lighter gauge of sheet metalstock than has heretofore been practical. For example, it is pointed outthat when the thread protector 33 is of a size to be applied to a pipeof approximately 2% inch nominal size, it was necessary heretofore tomake the protector out of sheet metal stock of 13 gauge. With theimproved construction here shown for the protector 33, the increasedrigidity I afforded by the hollow annular rim 38 makes it possible toconstruct the protector out of sheet metal stock of 16 gauge, or even alighter gauge, without materially sacrificing any strength or rigidityin the protector. The lighter gauge of sheet metal stock now used can bemore easily formed than the heavier gauge heretofore used and thereforeresults in an advantage in die expense, both as to initial die cost anddie maintenance.

Another important advantage resulting from the hollow annular rim 38 isa manufacturing advantage in that a protector of a smooth and regularshape and devoid of dangerous burrs and sharp corners can be made withfewer manufacturing operations. This is possible because during themanufacture of the thread protector 33 the sheet metal at the outer endof the sleeve 35 can usually be formed to its outwardly deflected andreversely curled condition during a single forming operation and, sincethe extreme annular end of the sleeve 35 is disposed in the finishedprotector in a position where it will not be engaged by the hands orclothing of the workmen handling the protector or the pipe carrying thesame, it will not require any trimming. or smoothing operation as hasheretofore been necessary to remove or eliminate such dangerous burrsand sharp edges.

The above-mentioned inwardly converging axial taper 39, provided on thethread protector 33 between the rim 38 and the helical thread 36thereof, constitutes another important feature of this protector becauseit cooperates with the internal chamfer 34 to produce new resultsincluding the centering of the outer end of the protector onthe fitting.31. The axially tapered portion 39 is constructed so that its outer endwill provide an annular shoulder or edge 39 of a diameter to wedginglyengage in the internal chamfer 34 when the protector 33 is screwed intothe fitting 31 for the distance necessary to cause the hollow annularrim 38 to engage the end face of the fitting. This wedging engagement ofthe annular shoulder or edge 39 not only centers the outer end of theprotector in the outer end of the fitting 31 but forms an annutar sealby the metal-tometal engagement between the protector and the fitting atthis point. Such a seal is desirable because it enables the protector toexclude foreign matter from the thread 32 which might otherwise corrodeor contaminate such thread.

In Fig. 5 of the drawing a thread protector 43 is shown which is of aconstruction similar to the thread protector 33 described above and inwhich the corresponding parts are designated by the same referencecharacters. The thread protector 43 is used in the same manner andaffords the same advantages as the above-described protector 33. Inaddition, the thread protector 43 carries a packing 44 at its outer endand which, is held in connected relation with the protector by having aholding portion 44 retained or locked in the annular recess of thehollow annular rim 38. The packing 44 also includes a ring portion 44which projects from the rim Y38 and is engageable with the end face 40of the coupling 31 when the protector is fully applied thereto.

The packing 44 may be a ring formed or" any material suitable forsealing purpose between the protector 43 and the fitting 31 such aspaper, asbestos or other fibrous material, rubber or rubber-likematerial, or a soft metal such as brass, copper, or aluminum. Thispacking ring can be assembled into connected relation with the protector44 without requiring any additional manufacturing operation, by simplyplacing the packing ring in a position to have the holding portion 44thereof engaged and confined in the recess 45 of the hollow rim 38 whenthe sheet metal of the outer end of the sleeve 35 is deflected into theabove-described reversely curled relation. Such deflection of thisportion of the sleeve 35 causes the annular portion 38 of the hollow rim33 to engage the packing ring 44 and press the same against the mainwall of the sleeve 35 with the relatively enlarged retaining portion 44confined-or locked in the recess 45.

When the protector 43 has been applied to the fitting 31, the packing 44will assist in causing the protector to be securely held on the fittingand will also assist in centering the outer end of the protector in theopen end of the fitting. This packing will also serve the purpose ofabsorbing some of the blows and shocks which are delivered against theouter end of the fitting during handling and shipping and will form aseal at the outer end of the fitting which will assist in excludingforeign matter which might otherwise corrode or contaminate the thread32.

From the accompanying drawing and the foregoing detailed description itwill now be understood that this invention provides an improvedconstruction for a thread protector to be used on a threaded fitting,pipe end, machine part or other member and which protector can be moreeconomically produced because the integral hollow annular rim formed onthe outer end of the protector stiffens and reinforces the same so' thata lighter gauge of sheet metal can be used. It will also be seen thatthis hollow annular rim has a springing and yielding action forabsorbing blows which might otherwise damage the threaded end of themember and this rim of itself, or assisted by a packing member or anannular chamfer, also forms a seal with the outer end of the member towhich the protector is applied and accomplishes a centering and lockingcooperation with such outer end by which the protector is held againstlateral shifting or accidental unscrewing. Additionally, it will be seenthat in the improved protector the hollow annular rim is'. of a radialwidth. and carries. knurling such that the peripheral edge thereof willextend beyond the periphery of. the member to which the protector isapplied and will facilitate the application or removal of the protectorby the use of a suitable tool or a handgrip. it will be seen,furthermore, that the use of the hollow annular rim at the outer end ofthe protector not only produces a stronger and more rigid protector froma lighter gauge of sheet metal, but the radially deflected and reverselycurled relation of the sheet metal of the outer end of the sleeve whichforms this hollow annular rim eliminates the need for trimming the sheetmetal, or performing other machine operations thereon at this pointwhich have heretofore been necessary to remove dangerous burrs and sharpedges.

Although the improved thread protector of the present invention has beenillustrated and described herein to a somewhat detailed extent, it willbe understood, of course, that the invention is not to be regarded asbeing limited correspondingly in scope, but includes all changes andmodifications coming within the spirit of the invention and the languageof the claim hereof.

Having thus described my invention, I claim:

A thread protector for application to a hollow member having a helicalthread on the inside thereof and also having an internal annular chamferat its outer end comprising, a one-piece sheet metal sleeve having agroup of thread elements thereon and engageable with said helical threadfor retaining the protector in connected relation with said member, thesheet metal of the extreme outer end of said sleeve being deflected soas to define a radially ofiset hollow annular rim formed by continuouslyconnected annular wall portions consisting of axially spaced first andsecond substantially radially extending flange portions and an axiallyextending portion connecting said second flange portion with said firstflange portion, said hollow annular rim forming a stilfening means andan external annular end seat on the outer end of said sleeve and beingof a radial width such that the outer periphery of said rim projectsbeyond the outer periphery of said member, said first flange portionforming an end wall on said protector at the outer end thereof and saidsecond flange portion forming said external annular end seat on saidprotector for seating engagement with the end face or" said member, saidsecond flange portion being an inturned annular flange portionterminating in a free annular edge presented toward and lying adjacentto the main wall of said sleeve at a point between said first flangeportion and said thread elements such that said free annular edge isrelatively shielded from injurious personal contact therewith, the sheetmetal of said sleeve also defining an axially inwardly convergingexternal annular taper on said protector adjacent said annular rim andadapted for seating engagement against the internal annular chamfer ofsaid member, said free annular edge being spaced from said main wall ofsaid sleeve by an intervening annular slot, and a packing retained insaid hollow annular rim and having an annular portion projecting fromsaid hollow rim through said annular slot for continuous annular sealingengagement with the end of said member adjacent the outer end of saidchamfer.

References Cited in the file of this patent UNITED STATES PATENTS2,001,248 Greene May 14, 1935 2,022,189 Engstrom Nov. 26, 1935 2,055,646Bosley Sept. 29, 1936 2,074,231 Meacham Mar. 16, 1937 2,098,087 EngstromNov. 2, 1937 2,121,436 Lytle June 21, 1938 2,385,408 Engstrom Sept. 25,1945 2,471,716 Bell May 31, 1949

